The leaves of blackberry are commonly affected with Orange Rust. The disease appears in the early spring as large, bright, orange - colored patches on the lower surface. The affected leaves are dwarfed and rolled slightly, exposing their rusted lower surfaces. Sometimes the rust patches are found on the canes. As a ruje, however, the canes and roots, although often infected, show little external indication of disease. It has been observed that affected plants are freer from prickles than normal plants. Healthy and diseased canes may be found in the same stool. All affected canes should be destroyed. The same disease also occurs on raspberries (see fuller discussion, page 399).